Methods of displaying 3D data sets from PET, SPECT, NMR and CT will be investigated with the goal of aligning Nuclear Medicine (PET, SPECT) images with these from CT and MRI. A visual, real time re-production technique will be employed. The project began in March, 1989, with the arrival of the imaging equipment. PET, SPECT (Tl) and MRI data sets have been acquired form cardiac studies of 15 subjects to date. A preliminary version of the re-production program has been implemented.1 An automated alignment program has been developed and tested which performs rotational, translational and size alternations necessary to accurately align PET and MRI cardiac images (transaxila slices) . It is based on definition of lung outlines for the attenuation PET scan and the MRI scan. This work has been accepted for publication in Computer in Cardiology (1990.